A polymer brush comprising a polymer which has one end fixed on a substrate is one of a surface modification means for a substrate, and is known to provide a characteristics such as hydrophilicity or low frictional properties on the substrate surface (patent documents 1, 2). The polymer brush is also suggested from a simulation to have a possibility to phase-separate between a polymer brush and a solvent phases when the polymer brush is placed in a certain solvent (non-patent document 1). There is, however, no example that achieved a phase-separation between a polymer brush and a solvent phases, and the exact method is not demonstrated.
Further, the phase-separation between a polymer and a solvent phases occurs only in the presence of a solvent, and the phase-separated structure is not known in a gas phase with no solvent existence. The realization method is not understood moreover. In light of technical application to devices, the availability of the polymer brush further advances with the achievement of a phase-separated structure in a gas phase. However, the phase-separated structure formation in a gas phase is not suggested in a simulation, and there is no implemented examples.